Method of making sheet-metal parts



June 12, 1962 KQLTON 3,038,430

METHOD OF MAKING SHEET-METAL PARTS Filed Dec. 50, 1959 INVENTOR DAVIDKOLTON ATTORNEY United rates @atent @fifiee 3,938,436 i atenteri June12, 1962 spasms NETHGD F MAKENG fiHEET-METAL PARTS David Koiton, Newark,NJ assignor to Federal Pacific Eiectric Company, a corporation ofDelaware Filed Dec. 30, 1959, Ser. 1 o. 862,333 2 Claims. (Cl. 113-116)The present invention relates to methods of forming metal parts.

An object of this invention is to avoid waste in making parts ofsheet-metal and more particularly parts having a split ring having anintegral strip extension. An element of this form is used as theelectrical terminal connection for a fuse holder, but it will beapparent that the concepts involved apply to other products.

As will be seen from the description of an illustrative embodiment shownin the drawings and described in detail below, the article is stampedfrom sheet-metal; and at least part of the strip portion extending fromthe ring is taken from the sheet-metal stock that would normally bewaste, within the ring. In order to do this, the slit in the ring isinitially made wide enough to provide material for the strip portion,even though that width is greater than is permissible in the finishedarticle; and portions of the ring are deformed either before or duringthe blanking operation. Thereafter the deformations are flattenedcausing the over-size width of the opening in the ring to close to thedesired dimension.

The nature of the invention will be better appreciated from thefollowing detailed description of the illustrative embodiment shown inthe drawings, wherein:

FIG. 1 is the plan view of the sheet-metal article to be formed;

FIG. 2 is the side elevation of the article in FIG. 1;

FIG. 3 is the plan view of a continuous series of metal blanks as theyare related to each other in the blanking process, the broken lines inFIG. 3 representing marginal edges of a strip of sheet-metal from whichthe blanked parts illustrated are taken; and

FIG. 4 is an end view of a part in FIG. 3, viewed from the right.

Referring now to the drawings, the article in FIGS. 1 and 2 is seen toinclude a split-ring It} with a strip 12 extending integrally from thering, this article having a slit or gap 14 that is opposite stripportion 12. A hole 16 is provided in strip 12, screw-threaded asillustrated. The ring forms a contact for a fuse in a fuse holder. Thisring is to be forced into an opening whose diameter is less than thering diameter, and snaps below an overhang so as to be fixed inposition. During this inserting operation, the gap 14 is reduced and theinherent resilience of the ring 16 causes the ring to resume the shapeillustrated, becoming self-locked in position. The strip 12 is bent tomeet the requirements of the fuse holder.

If such a part were to be stamped from sheet-metal as is readilyfeasible, the hole left by piercing a disc from ring 1% would representconsiderable waste, and the cost of this article would be unduly high.In accordance with the present invention, a method is provided whichavoids most of this waste.

As illustrated in FIGS. 3 and 4, a series of parts 2% are stamped out ofsheet-metal stock 18. The strips 12 are shown disposed within the ringsit) in the relative positions they occupy in the stamping operation.There is no wasted disc within ring 10. However, the width of strip 12is considerably greater than would normally be available at gap 14; andfor this reason the edges 14' of ring it) are spaced apart much greaterduring the stamping operation than would be permissible in the finishedproduct. Either prior to or during the blanking operation, orimmediately after the blanking operation with the portions of ring illfixed in the relative positions illustrated, dimples 22 are formed inthe sheet-metal remote from edges 14', these dimples being of greaterextent at the outside edges of ring 10 than at the inner edges of thatring.

Subsequently, handling parts 2% individually so that the space betweenedges 14'14 is left vacant, dimples 22 are flattened. This has theefiect of closing the wide space between edges 14 as illustrated in FIG.3 so that they assume the required spacing in FIG. 1.

It is evident that the described illustrative embodiment of thisinvention is readily adaptable to articles of various shapes, andtherefore the invention should be broadly construed in accordance withits full spirit and scope.

Having thus described my invention, what I claim and desire to secure byLetters Patent is:

l. The method of making an article having a split ring and a stripextending integrally from the ring from a length of sheet-metal stockmaterial, the split in the ring being narrower than the width of thestrip, including the steps of blanking and forming the strip and splitring with dimples therein, the split in the ring portion being largeenough to provide material for the strip portion of another like articleto be blanked from the sheet-metal stock, and with the dimples in saidring portion being at points remote from the edges of the split, thedimples being deeper at the outside edges of the ring than at the insideedges of the ring, and thereafter flattening the dimples to reduce thewidth of the split to the required size.

2. The method of making an article having a split ring provided with aninner and an outer periphery and a strip extending integrally from theouter periphery of the ring from a length of sheet-metal stock material,the split in the ring being narrower than the width of the strip,including the steps of blanking and forming the split ring with dimplestherein, the split in the ring portion being large enough to providematerial for the strip portion of another like article to be blankedfrom the sheet-metal stock, and with a plurality of the dimples spacedalong the outer periphery of the ring, the dimples being deeper at theouter periphery of the ring than at the inner periphery of the ring, andthereafter flattening the dimples to reduce the width of the split tothe required size.

Lang a Aug. 21, 1945 Engel Dec. 13, 1949

